Study Of MACh-receptor And Tight Junctions In The Protective Mechanism Of Ischemic Preconditioning On The Transplanted Submandibular Gland

Purpose:Keratoconjunctivitis sicca is a multifactorial disease of ocular surface damage and ocular symptoms, because of abnormalities of tear quality and quantity, hemodynamic abnormalities, decreased tear film stability, seriously affecting the quality of life of patients. Artificial tears, Punctal closure, Lacrimal embolism can be treated for mild keratoconjunctivitis sicca, which don’t work for severe keratoconjunctivitis sicca. The procedure of autotransplantation of the submandibular gland (SMG) has been reported as an effective treatment method with the development of microsurgery.The procedure of autotransplantation of SMG consists of denervation and ischemia/reperfusion (I/R). Previous studies have identified that denervation of the transplanted glands, following substantial reduction of neurotransmitter release, could lead to secretion dysfunction of the transplanted SMGs. Meanwhile, the injury-stress response caused by I/R also leads to secretion dysfunction. Ischemic preconditioning (IPC) shows the potential to relieve the injury. Paracellular pathway is the main way of water transport in the submandibular gland, and tight junction structure is an important structure which plays an important role of the secretion.Here, we try to research the alteration of mACh-receptor and tight junctions about the transplanted submandibular gland after IPC, and to explain the protective mechanism of IPC on the rat submandibular gland after IR injury.Methods:In-situ I/R and IPC experimental models of submandibular glands of healthy male Wistar rats were conducted. For I/R groups, the glands were subjected to 90 min of ischemia without denervation, followed by 1,12,24, or 72h of reperfusion. IPC was achieved by 3 min of ischemia following 3 min of reperfusion, performed three times before I/R. The right glands were operated on and the left glands served as the control. Salivary secretion, histological changes, alternations of tight junctions (TJs) and mACh-receptor levels were detected.Results:The secretory function of the glands decreased at 1 and 12h, and the saliva secretion gradually had the same value as that of the control sample 72h after reperfusion. Cellular atrophy, inflammatory cells infiltration, tissue edema, the collapse and reduced widths of TJs were observed especially after reperfusion for 12h. The level of mACh-receptor exhibited the same tendency, and lower mACh-receptor levels 12h after reperfusion were observed. Comparatively, IPC showed the potential to relieve the injury caused by I/R. Conclusions:I/R can cause the reducing of mACh-receptor, the injury of TJs and glands, which might have an important role in the secretion of submandibular glands, comparatively, IPC showed the potential to relieve the injury of the transplanted submandibular glands through regulating mACh-receptor and TJs.